The present invention relates to a means for reducing or maintaining intraocular pressure. More particularly it relates to a method and composition for reducing or maintaining intraocular pressure involving the administration of a composition containing a 9,15-diacyl ester prostaglandin in an ophthalmically acceptable carrier.
The method and compositions of the present invention are particularly useful for the management of glaucoma, a disease of the eye characterized by increased intraocular pressure. On the basis of its etiology, glaucoma has been classified as primary or secondary. For example, primary glaucoma in adults, congenital glaucoma, may be either chronic open-angle or acute or chronic angle-closure. Secondary glaucoma results from pre-existing ocular diseases such as uveitis, intraocular tumor or an enlarged cataract.
The underlying causes of primary glaucoma are not yet well known. The increased intraocular tension is due to obstruction of aqueous humor outflow. In chronic open-angle glaucoma, the anterior chamber and its anatomic structures appear normal, but drainage of the aqueous humor is impeded. In acute and chronic angle-closure glaucoma, the anterior chamber is shallow, the filtration angle is narrowed and the iris may obstruct the trabecular meshwork at the entrance to the canal of Schlemm. Dilation of the pupil may push the root of the iris forward against the angle or may produce pupillary block and thus precipitate an acute attack. Eyes with narrow anterior chamber angles are predisposed to acute angle-closure glaucoma attacks of varying degrees of severity.
Secondary glaucoma is caused by any interference with the flow of aqueous humor from the posterior chamber into the anterior chamber and subsequently, into the canal of Schlemm. Inflammatory disease of the anterior segment may prevent aqueous escape by causing complete posterior synechia in iris bombe, and may plug the drainage channel with exudates. Other common causes are intraocular tumors, enlarged cataracts, central retinal vein occlusion, trauma to the eye, operative procedures and intraocular hemorrhage.
Considering all types together, glaucoma occurs in about 2% of all persons over the age of 40 and may be asymptomatic for years before progressing to rapid loss of vision. In cases where surgery is not indicated, topical .beta.-adrenoceptor antagonists have traditionally been the drugs of choice for treating glaucoma.
Certain eicosanoids, specifically C-1 esters of certain prostaglandins, have been reported to possess ocular hypotensive activity. However, prostaglandin ocular hypotensives generally suffer from the disadvantage of inducing conjunctival hyperemia of varying severity and duration, smarting, and foreign body sensation, as well as presenting solubility problems in certain ophthalmically advantageous carriers.
This invention relates to derivatives of the known prostaglandins formulated in a pharmaceutically acceptable vehicle, and ophthalmic use of those prostaglandins. The present invention is advantageous in that ocular hypotension is achieved with a reduced incidence of ocular surface hyperemia.